CN107152648B

CN107152648B - Improved lens for a lighting device of a motor vehicle

Info

Publication number: CN107152648B
Application number: CN201710122358.5A
Authority: CN
Inventors: 玛丽·佩拉林; 戴维·布兰丹; 斯特凡纳·安德烈
Original assignee: Valeo Vision SAS
Current assignee: Valeo Vision SAS
Priority date: 2016-03-02
Filing date: 2017-03-02
Publication date: 2021-03-09
Anticipated expiration: 2037-03-02
Also published as: EP3214364A1; US20170254496A1; EP3214364B1; US10190741B2; FR3048485A1; FR3048485B1; CN107152648A

Abstract

Lens for a lighting device of a motor vehicle, comprising a rear surface designed to be oriented towards a light source of the lighting device and a convex front surface (18) designed to be oriented towards a road being illuminated, the lens (10) having a median vertical plane (P) designed to be substantially orthogonal to the road, the front surface having a first diffusion zone (Z1) with microstructures (20) adapted to diffuse the light emitted by the light source, the first diffusion zone (Z1) extending in the median vertical plane (P), the front surface further comprising at least two second diffusion zones (Z2)₁、Z2₂) Each second diffusion region having a microstructure (20) adapted to diffuse light emitted by the light source, two second diffusion regions located on each side of the median vertical plane, two second diffusion regions (Z2)₁、Z2₂) Has a depth which is substantially greater than the depth of the microstructure (20) of the first diffusion zone (Z1).

Description

Improved lens for a lighting device of a motor vehicle

Technical Field

The present invention relates to the field of lenses for lighting devices of motor vehicles, and more particularly to the field of lenses for lighting devices adapted to provide low beam and high beam functions.

Background

This type of device usually comprises two light sources each associated with one of these functions, for example one of the light sources is illuminated when a low beam function is performed and both light sources are illuminated when a high beam function is performed.

Typically, this type of device also comprises elements such as folds or masks configured to produce cut-off lines in the light beam produced by the device, in particular when performing a low-beam function. The configuration of the cut-off line is specified by regulations which specify, for example, that the cut-off line will form a boundary with a given light gradient between the illuminated space and the dark space above it.

One of the disadvantages of the present lighting devices is that the cut-off line in question is still clearly marked when performing the high beam function and forms a dark band between the high beam and the low beam. Moreover, the clear boundary between the two beams tends to interfere with the driver's vision.

Disclosure of Invention

The present invention aims to improve the situation.

The invention therefore relates to a lens for a lighting device of a motor vehicle, said lens comprising a rear surface and a front surface, the rear surface being designed to be directed towards a light source of the lighting device, the front surface being designed to be directed towards the road being illuminated, the lens having a median vertical plane designed to be substantially orthogonal to a road, the front surface having a first diffusion zone having microstructures adapted to diffuse light emitted by the light source, the first diffusion region extends in a median vertical plane, the front surface further comprising at least two second diffusion regions, each second diffusion region having a microstructure adapted to diffuse light emitted by the light source, the two second diffusion regions being located on each side of the median vertical plane, the microstructures of the two second diffusion regions having a depth substantially greater than the depth of the microstructures of the first diffusion regions.

According to a first aspect of the invention, the ratio between the depth of the microstructure of the two second diffusion regions and the depth of the microstructure of the first diffusion region is between 1.5 and 3.

According to one aspect of the invention, the microstructure of the first diffusion region has a depth of between 1.5 μm and 4 μm.

According to one aspect of the invention, the microstructure of the second diffusion region has a depth of between 3 μm and 8 μm.

According to one aspect of the invention, the depth of the microstructure of one second diffusion region is substantially greater than the depth of the microstructure of the other second diffusion region.

According to one aspect of the invention, the microstructures in a given diffusion region all have substantially the same depth.

According to one aspect of the invention, the microstructures have a maximum radius of between 0.5mm and 1 mm.

According to one aspect of the invention, the first diffusion region has a substantially strip-like shape extending in a median vertical plane.

According to one aspect of the invention, the first diffusion region has a substantially circular shape.

According to one aspect of the invention, the first diffusion region has a width of between 20% and 60% of the diameter of the lens.

According to one aspect of the invention, the front surface comprises a third diffusion region extending substantially orthogonally to the median plane, the third diffusion region extending from the lower ends of the first and second diffusion regions towards the end of the front surface of the lens.

According to an aspect of the invention, the third diffusion region has a microstructure adapted to diffuse light emitted by the light source, the microstructure of the third region having a depth substantially equal to the depth of the microstructure of the first diffusion region.

According to one aspect of the invention, the first and third diffusion regions together define a connecting diffusion region on the front surface of the lens.

According to one aspect of the invention, the front surface has, at the level of one lower end, an area formed to divert a portion of the light from the light source to illuminate the elevated sign.

The invention also relates to a lighting device, in particular for a motor vehicle, comprising at least one light source designed to emit light and a lens according to any one of the preceding claims, which is arranged to receive at least part of the light emitted by the light source.

According to one aspect of the invention, the lighting device comprises a first light source associated with a low-beam function of the lighting device, a second light source associated with a high-beam function of the lighting device, and a cut-off element adapted to generate a cut-off line within the light beam emitted by the lighting device.

Drawings

The invention will be better understood by perusal of the following detailed description, given by way of example only, and with reference to the accompanying drawings, in which:

figure 1 is a schematic view of a lighting device according to the invention;

figures 2a and 2b illustrate the light beams produced by the device of figure 1 when performing one and the other of the two functions of the device of figure 1;

figure 3 is a front view of a lens according to the invention; and

fig. 4 illustrates a cross-sectional view of the microstructure of the lens of fig. 3.

Detailed Description

Fig. 1 illustrates a lighting device 2 according to the invention, hereinafter referred to as device 2.

In the context of the present invention, the device 2 is advantageously a lighting device of a motor vehicle, i.e. it is intended to be integrated in a motor vehicle.

Moreover, the device 2 is advantageously a headlamp.

Advantageously, the device 2 is adapted to perform two different lighting functions:

-low beam function, and

-a high beam function.

The light beam generated by the device 2 when performing the low beam function is illustrated in fig. 2 a. In its upper part, it has a cut-off line C which borders a zone illuminated by the light beam and located below the cut-off line C, with a black dark zone located above it, which is not illuminated.

For example, the cut-off line exhibits a first linear portion at its left part and a second linear portion at its right part. The second linear portion is located, for example, at a height different from that of the first portion. The two sections are separated by an intermediate sloping section.

The light beams generated by the device 2 when performing the high beam function are illustrated in fig. 2 b. The beam exhibits in the lower part substantially the same configuration as in fig. 2a and it also exhibits a luminous zone above the cut-off line C, said cut-off line thus separating the two luminous zones.

Referring again to fig. 1, the apparatus 2 comprises a housing 4, at least one light source 6, an element 8 configured to produce a cut-off line C, and a lens 10 according to the invention.

The housing 4 is configured to include one or more light sources 6. It is also configured to reflect light emitted by these light sources in the direction of the lens 10.

The housing 4 comprises, for example, an upper part 12 and a lower part 14, which are respectively associated with at least one of the two functions of the device 2. More specifically, the upper portion 12 is associated with low and high beam functions, and the lower portion 14 is associated with high beam functions only.

The upper portion 12 comprises, for example, a plurality of curved half-shells, which are paired with one another in the region of their transverse ridges, and whose respective concave faces face the element 8. Each shell has, for example, an ellipsoidal shape.

For example, the upper portion 12 includes three such shells.

The lower part 14 is, for example, in the shape of a shell, the concavity of which faces the element 8 and the upper part 12 of the casing 4. This has for example a substantially ellipsoidal shape.

Alternatively, the lower part 14 comprises a plurality of said shells, which are paired with each other in the region of their transverse ridges, and whose respective concavities face the element 8 and the upper part 12.

The inner surfaces of the upper and

lower parts

12, 14 are configured to reflect light emitted by the one or more light sources 6.

One or more light sources 6 form the core of the light emission of the device 2.

Advantageously, the device 2 comprises two light sources 6 independent of each other.

Thus, the device 2 comprises a first light source 6₁And a second light source 6₂The first light source is associated with a low beam function and a high beam function, and the second light source is associated with a high beam function only.

Light source 6₁Is arranged within the housing to emit light in the direction of the inner surface of the upper portion 12 of the housing 4.For example, it is arranged in the region of the focal point of the shell of the upper part 12. In practice, it is arranged, for example, in the region of the element 8.

Light source 6₂Is arranged within the housing to emit light in the direction of the inner surface of the lower part of the housing 4. For example, it is arranged in the region of the focal point of the lower part 14.

Each light source for example comprises one or more light emitting elements, for example light emitting diodes, optionally coupled with a luminophore material designed to convert a part of the light emitted by these elements in order to obtain a combined light of a selected color. The resultant light is, for example, white.

The element 8 is configured to produce a cut-off line C within the light beam produced by the device 2.

The element 8 comprises a portion forming a fold, i.e. a mask reflecting in a selected manner to give a cut-off line C of the desired shape. The portions forming the folds are for example arranged substantially horizontally (in the direction of the orientation of fig. 1). Which is located in the region of the front end of the element 8.

The folded portion has, for example, a left ridge portion designed to form a first straight portion of the cut-off line C, a right ridge portion offset in height from the left ridge portion and designed to form a second straight portion of the cut-off line C, and an inclined intermediate ridge portion designed to form an inclined intermediate portion of the cut-off line C.

The element 8 also comprises a portion forming a support for the one or more light sources 6. This part is located behind the element 8, as shown in fig. 1, as opposed to the part in front of it that forms the fold.

In the example of fig. 1, the two portions have been represented as a single piece of material. Alternatively, they may be separate from each other.

Referring to fig. 3, the lens 10 is configured to shape the light arriving at the lens from the light source 6 and the housing 4 to produce an outgoing beam (as shown in fig. 2a and 2b depending on the function performed).

The lens is located on an optical path of light supplied by the light source after being reflected on an inner surface of the housing. For example, the lens is held in a fixed position relative to the housing 4 by a frame (not shown).

In the context of the present invention and as described later, the lens 10 is also configured to blur the cut-off line C, in particular when performing a high beam function.

The lens 10 is a spherical form lens. Advantageously, it is of the convergent type. In a front view, the lens exhibits a substantially circular shape. The diameter of the lens 10 (in the direction of the substantially circular shape) is for example between 35mm and 85 mm.

The lens 10 is made of glass, for example. Alternatively, it is made of Polymethylmethacrylate (PMMA) or Polycarbonate (PC).

The lens 10 has a substantially horizontal optical axis (in the direction of the orientation of fig. 1). The optical axis is, for example, substantially at the same height as one of the ridges of the element 8 (e.g., its left ridge).

The lens is arranged facing the housing 4. Advantageously, it is centred with respect to the housing 4.

The lens 10 has a rear surface 16 designed to be directed towards the housing 4 and a front surface 18 designed to face the road being illuminated.

The rear surface 16 forms an entrance face for light entering the lens 10. The rear surface is for example flat. However, alternatively, the rear surface has a convex surface or any desired shape.

The front surface 18 forms an exit face for light. The front surface 18 is convex, for example. Alternatively, it may have any desired shape. For example, in one variant it is flat.

The lens has a median plane P which is designed to be substantially vertical with respect to the road being illuminated. Here, the median plane refers to a plane separating the right part of the lens from the left part thereof, particularly in a front view of the lens. In the example of fig. 3, the lens is shown in a front view, said plane P being orthogonal to the plane of fig. 3.

Optionally, as shown in fig. 3, the lens 10 is substantially symmetrical about the plane P. However, it is not excluded that the lens is asymmetric with respect to this plane.

Optionally, as shown in fig. 3, the lens has an upper flat portion and/or a lower flat portion, each flat portion defining a surface that is substantially flat and substantially orthogonal to plane P. The flat portion is provided, for example, to reduce the vertical footprint of the lens. For example, for a lens having a diameter of 70mm, the flat is provided such that the height of the lens along plane P is substantially equal to 60 mm.

In the context of the present invention, the front surface 18 has microstructures 20 adapted to diffuse the light passing through the lens, in particular to blur the cut-off line C.

As shown in fig. 4, "microstructure" refers to a roughness formed on the surface of the front surface 18. For a given region of front surface 18, the asperities may be regularly distributed, i.e., the pattern defined by peaks and valleys is regular within the given region, or they may be distributed in an irregular manner.

These microstructures are present, for example, in the shape of depressions in the surface of the front surface.

Advantageously, the microstructure has a mouth of substantially circular shape. The radius of the mouth forms the maximum radius of a particular microstructure. In the context of the present invention, the maximum radius of the microstructures 20 is advantageously between 0.5mm and 1 mm.

The microstructures 20 likewise have a given depth, as described below.

Referring to FIG. 3, front surface 18 has a first diffusion zone Z1 and two second diffusion zones Z2₁、Z2₂Said first diffusion regions comprise microstructures 20 adapted to diffuse light from the light source 6 and both second diffusion regions likewise comprise microstructures adapted to diffuse light from the light source 6 as well. These microstructures have the purpose in particular of blurring the cut-off line C.

The microstructure 20 of the first diffusion zone Z1 has a depth that is substantially less than the depth of the second diffusion zone Z2₁、Z2₂Of the microstructure 20.

More specifically, first zone Z1 extends along medial plane P on front surface 18. Advantageously, plane P forms a plane of symmetry of zone Z1.

Zone Z1 has a width (i.e., a dimension transverse to plane P) that is between 20% and 60% of the diameter of the lens.

Within zone Z1, the microstructures advantageously all have substantially the same configuration and, in particular, substantially the same depth.

The depth of the microstructures 20 of zone Z1 is advantageously between 1.5 μm and 4 μm.

Furthermore, the microstructures are optionally regularly distributed within the region. For example, they are regularly distributed there in a concentric manner with respect to a given point. This point is for example the centre of the front surface, which is for example at half the height of the front surface 18 along the plane P. Alternatively, the spatial distribution of microstructures 20 is non-concentric. Which is for example substantially a matrix, the microstructures being arranged in rows and columns. These rows and columns are for example orthogonal or respectively parallel to the plane P. Again alternatively, their distribution within this zone Z1 is irregular.

Zone Z1 is for example in the form of a strip extending in plane P. The belt has, for example, a substantially rectangular shape. The transverse edges of the belt are substantially perpendicular to the plane P and the longitudinal edges are each located on either side of the plane P symmetrically with respect to each other with respect to the plane P. The upper transverse edge of the belt corresponds, for example, to the upper end of the front surface 18. The lower transverse edge is for example located at a distance from the upper transverse edge equal to half the length of the front surface along plane P.

In this configuration, zone Z2₁And Z2₂Located on each side of zone Z1.

Alternatively, zone Z1 has a generally circular shape (as shown in phantom in fig. 3).

Advantageously, when the microstructures are arranged concentrically, the center of zone Z1 then coincides with the concentric center of microstructures 20. For example, in the example of fig. 3, the center substantially corresponds to the center of the front surface. This facilitates the design of the lens, since it is then easier to ensure that no microstructures are located at the boundary of zone Z1.

In some embodiments, such as the embodiment of FIG. 3, the upper end of zone Z1 is located at a distance from the upper end of the anterior surface of the lens along plane P. In these embodiments, zone Z2₁And Z2₂The boundary of plane P is formed in the region of the front surface between the upper end of the lens and the upper end of zone Z1.

Alternatively, the upper end of zone Z1 is located in the region of the upper end of the front surface of the lens. For example, the upper end of zone Z1 is formed by a portion of a ridge bounded by the upper flat and the front surface (e.g., by a point of the ridge, in which case zone Z1 is tangent to the upper end of the front surface, or by a section of the ridge).

In certain embodiments, such as the embodiment of FIG. 3, the lower end of zone Z1 is formed by a chord of generally circular shape that is orthogonal to plane P. In other words, the zone Z1 has a substantially circular shape with its lower end truncated.

As described in more detail below, the lower end of zone Z1 is the boundary of the third diffusion zone regardless of the shape of zone Z1.

Second zone Z2₁、Z2₂Extending on each side of plane P. They advantageously extend as far as the lateral edges of the lens 10. Their lower ends are for example located at the same height as the lower ends of zone Z1 along plane P. The respective shapes of these two zones are symmetrical with respect to each other, for example with respect to plane P.

In certain embodiments, such as the embodiment of fig. 3, the upper end is located at a height, such as an upper end of the front surface, such as a height of the upper flat portion. Alternatively, depending on the configuration of zone Z1, and particularly on its width when it has the shape of a belt, the upper end may be located away from the flat.

As previously described, in zone Z2₁、Z2₂The microstructures 20 advantageously all have substantially the same configuration, in particular substantially the same depth.

Zone Z2₁、Z2₂Advantageously between 3 and 8 μm deep.

Also, the second diffusion region Z2₁、Z2₂The ratio between the depth of the microstructure of (a) and the depth of the microstructure of the first diffusion zone Z1 is between 1.5 and 3.

Moreover, advantageously, zone Z2₁、Z2₂The depth of the microstructures 20 of one of these zones is greater than the depth of the microstructures of the other of these zones.

Advantageously, the greater depth is in the zone Z2 opposite the ridge of the fold 8 on the optical axis of the lens 10₁、Z2₂Is internally observed. In the example of the figure in which the left ridge of the fold is on the optical axis of the lens, zone Z2₂Microstructure 20 to zone Z2₁Is deeper.

For example, in one embodiment, zone Z2₁Has a depth of 4.7 μm, and a zone Z2₂The depth of the microstructure of (2) is substantially 5.4 μm. The depth of the microstructure of zone Z1 is then, for example, substantially 2.4 μm.

Like the first diffusion zone Z1, the microstructure of these second zones is, for example, regularly distributed in zone Z2₁、Z2₂And (4) the following steps. They are here arranged concentrically, or in a matrix arrangement, or in any other regular arrangement.

Instead, they are not distributed in a regular manner here.

Referring again to fig. 3, the front surface 18 advantageously also comprises a third diffusion zone Z3, which extends transversely to the median plane. For example, it extends upwardly from a lateral edge of the lens to an opposite lateral edge. Advantageously, the shape of zone Z3 is substantially symmetrical about plane P.

Diffusion zone Z3 has microstructures 20 adapted to diffuse light passing through it. Advantageously, the depth of the microstructure of zone Z3 is similar to that of zone Z1. Moreover, their arrangement is advantageously the same as that of zone Z1.

Zone Z3 and zone Z1 and zone Z2₁、Z2₂Adjacent to each other. Which extend from the lower end of these zones towards the lower end of the lens. The upper end of which is in the zones Z1, Z2₁、Z2₂Is bordered on the lower end. For example, the upper end extends substantially orthogonal to the plane P from one side of the front surface to the other.

Zone Z3 forms together with zone Z1 a contiguous diffusion region of the front surface. In other words, the area formed by these zones is a continuous area within which the properties of the microstructure are advantageously substantially constant.

Optionally, the front surface 18 also has an area 22 at the level of its lower end, which is formed to divert the light arriving there in order to illuminate the elevated sign.

As shown, the elevated sign corresponds to an element such as a sign plate located at a higher point than the light beam (in the low-beam and high-beam functions) formed by the device 2. The area 22 is thus configured to divert a small portion of the light to illuminate the high points, for example, in a direction as dictated by regulations.

This zone 22 is, for example, adjacent zone Z3 and extends between the lower end of zone Z3 and the lower edge of the lens (optionally bounded by a lower flat).

Advantageously, these zones Z1, Z2₁、Z2₂Z3 and 22 collectively occupy substantially the entire front surface.

The mode of operation of the device 2 will now be described with reference to the accompanying drawings.

When the light sources 6 are driven by electrical energy, for example from electrical energy supplied by a power supply (not shown) of the device 2, these light sources emit light towards the inner surface of the corresponding portion of the housing 4. Where it is reflected in the direction of the lens 10, which shapes it. In particular, the light images the ridge of the fold 8, which is transformed by the appearance of the cut-off line C within the beam of light produced.

In the low beam function, only the light source 6₁Is energized so that the composite beam corresponds to that illustrated in fig. 2a (the light regions for elevated signs illuminated by the presence of region 22 are not shown).

In the high beam function, the light source 6₁And 6₂Are energized and the composite beam is illustrated in fig. 2 b.

Due to diffusion zones Z1, Z2₁、Z2₂The presence of Z3 and in particular the selective depth of the microstructure of these zones, the cut-off line C appears to be more blurred in the high beam function than in the prior art devices.

Specifically, the ambiguity of the cut-off line C is greater at locations away from the axis than at the axis, e.g., lateral locations more than 5 ° apart to the left and right of the axis (the two locations of 5 ° on each side of the axis are commonly referred to as 5 ° L and 5 ° R (L for left and R for right)).

In practice, zone Z2 at the side of the front surface of the lens₁And Z2₂Tends to reduce the light gradient in the lateral region of the cut-off line from the light source specifically associated with the high beam function.

For example, in the low beam function, the gradient of the cut-off line is between 0.15 and 0.40 for positions less than 10 ° on each side of the axis (i.e. for positions between 10 ° L and 10 ° R).

For these same positions, the gradient of the cut-off line in the high beam function is between 0.03 and 0.15.

In the prior art device, the gradient is substantially the same in both functions (high beam and low beam).

A method of manufacturing the lens 10 according to the present invention will now be described.

The lens 10 is advantageously manufactured by moulding with the aid of a mould. The mold has an inner surface designed to form the anterior surface of the lens. This inner surface of the mold has microstructures that are in a configuration that is complementary to the configuration of the microstructures that the front surface of the lens should have.

The microstructure of the mold is formed, for example, in a known manner. For example, for irregular distribution of the microstructure, they are formed by sand blasting, or formed by electrochemical etching. For a regular distribution of microstructures, the microstructures of the mold are formed, for example, by high speed machining of the mold.

In practice, one is to arrange microstructures in the surface of the mold to define zones complementary to zones Z1 to Z3 and zone 22 and constituting the material of the lens or the lead of the lens to define these zones.

Once the lens has been stripped from the mold, it may, for example, be subjected to an optional known treatment.

The lens according to the invention has several advantages.

In fact, it is possible to reduce the risk that the presence of the cut-off line C is liable to be generated for the driver, in particular in the high beam function, and in particular to reduce the nuisance caused by this cut-off line in the region of the lateral ends of the beam generated (and which is most likely to cause problems).

Moreover, the result is obtained in a simple manner without the need for significant modifications to the lighting device, in particular its geometric configuration.

In the above description, the apparatus 2 has been described as comprising a housing 4 having a reflective surface configured to reflect light emitted by the light source in the direction of the lens 10.

In an alternative configuration, the device 2 does not have a housing 4 with an internal reflective surface.

The device 2 then comprises a support on which the light source 6 is arranged. The support is for example arranged behind the element 8 and orthogonal to the optical axis of the lens. Light source 6₁And 6₂Arranged above and below the optical axis.

For each light source, the device further comprises a shaping optical element arranged opposite the corresponding light source and configured to focus the light emitted by the corresponding light source on the fold of the element 8.

For example, the relative configuration of the folds and lenses remains unchanged.

Claims

1. A lens for a lighting device of a motor vehicle, comprising a rear surface (16) designed to be oriented towards a light source (6) of the lighting device and a front surface (18) designed to be oriented towards a road being illuminated, the lens (10) having a median vertical plane (P) designed to be substantially orthogonal to the road, the front surface having a first diffusion zone (Z1) with microstructures (20) adapted to diffuse the light emitted by the light source, the first diffusion zone (Z1) extending in the median vertical plane (P), the front surface further comprising at least two second diffusion zones (Z2)₁、Z2₂) Each second diffusion region having a microstructure (20) adapted to diffuse light emitted by the light source, two second diffusion regions located on each side of the median vertical plane, two second diffusion regions (Z2)₁、Z2₂) Has a depth which is substantially greater than the depth of the microstructure (20) of the first diffusion zone (Z1).

2. Lens according to claim 1, wherein two second diffusion zones (Z2)₁、Z2₂) The ratio between the depth of the microstructure of (a) and the depth of the microstructure of the first diffusion zone (Z1) is between 1.5 and 3.

3. A lens according to claim 1 or 2, wherein the depth of the microstructure of the first diffusion zone (Z1) is between 1.5 μm and 4 μm.

4. The lens of claim 1, wherein the second diffusion zone (Z2)₁、Z2₂) The depth of the microstructure of (2) is between 3 μm and 8 μm.

5. The lens of claim 1 wherein the depth of the microstructure of one second diffusion region is substantially greater than the depth of the microstructure of the other second diffusion region.

6. The lens of claim 1 wherein the microstructures in a given diffusion region all have substantially the same depth.

7. The lens of claim 1, wherein microstructures have a maximum radius of between 0.5mm to 1 mm.

8. The lens of claim 1, wherein said first diffusion zone (Z1) has a substantially ribbon-like shape extending in a median vertical plane.

9. The lens of claim 1, wherein the first diffusion region has a substantially circular shape.

10. The lens of claim 1, wherein the first diffusion region has a width of between 20% to 60% of the diameter of the lens.

11. A lens according to claim 1, wherein the front surface comprises a third diffusion zone (Z3) extending substantially orthogonally to the median plane (P), the third diffusion zone extending from the lower ends of the first and second diffusion zones towards the end of the front surface (18) of the lens.

12. A lens according to claim 11, wherein the third diffusion zone (Z3) has a microstructure (20) adapted to diffuse the light emitted by the light source, the microstructure of the third zone having a depth substantially equal to the depth of the microstructure of the first diffusion zone (Z1).

13. A lens according to claim 11 or 12, wherein the first and third diffusion zones (Z1, Z3) together define a connecting diffusion region on the front surface (18) of the lens.

14. The lens of claim 1, wherein the front surface has an area (22) at the height of one lower end formed to divert a portion of the light from the light source to illuminate an elevated sign.

15. A lighting device, in particular for a motor vehicle, characterized in that: the lighting device comprises at least one light source (6) designed to emit light and a lens (10) according to any one of the preceding claims, which is arranged to receive at least a portion of the light emitted by the light source (6).

16. The lighting device according to claim 15, comprising a first light source (6)₁) A second light source (6)₂) And a cut-off element (8), the first light source being associated with a low-beam function of the lighting device and the second light source being associated with a high-beam function of the lighting device, the cut-off element being adapted to produce a cut-off line (C) within the light beam emitted by the lighting device.